Paper feeding device

ABSTRACT

A paper feeding device comprises a supporting frame, a pickup roller assembly, a paper blocking unit, a base and a sensor. The paper blocking unit is placed beside the pickup roller assembly, having a paper blocking element connected to the supporting frame, including a connecting portion, the connecting portion extends downwards to form a paper blocking arm. The sensor is located in the base, having an emitting arm and a receiving arm. The lower portion of the paper blocking arm can be located between the emitting arm and the receiving arm or depart from them for turning off/on the sensor. The paper feeding device decides whether the paper is provided on the base by the turn on/off status of the sensor, so an additional obstructer is avoided. Compared with conventional paper feeding device, the structure of the present invention is simple, and it is convenient to assemble.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper feeding device, and more particularly to a paper feeding device including a paper sensor which senses whether a sheet of paper is loaded.

2. The Related Art

Recent business machines, such as a scanner, a printer, a copier, etc., are broadly required in the office operation. The business machine has a function of image disposing. Take a conventional scanner as an example. An image disposing system of the scanner includes a glass plate, an optical system arranged under the glass plate for reading the image of the document placed on the glass plate. As a result of the application of an ADF (automatic document feeder), a stack of documents are placed in a document tray of the ADF, then the documents are fed into the scanner and placed on the glass plate one by one by a paper feeding device of the ADF, at last, the optical system reads the image of the document.

In the scanner, the paper feeding device further comprises a paper sensing unit which senses whether a sheet of paper is loaded. A conventional sensing unit includes a sensor and an obstructer. The sensor is U-shaped and arranged in a base of the paper feeding device, which has an emitting arm radiating light and a receiving arm receiving the light radiated from the emitting arm. The obstructer is rotatablely connected to the base, having a contacting arm and an obstructing arm. The contacting arm stretches out of the top surface of the base and the obstructing arm is arranged in the base. When the paper is not loaded on the base, the obstructing arm is placed between the emitting arm and the receiving arm, then the light radiated from the emitting arm is blocked by the obstructing arm and the receiving arm can not receive the light, so the sensor stays in a turn-off status. In this situation, the pickup roller assembly wouldn't pick paper, even though a paper-picking signal is detected. When the paper is loaded on the base, the front end of the paper pushes the contacting arm to rotate anti-clockwise, so the obstructing arm also rotates anti-clockwise and departs from the sensor, as a result, the light radiated from the emitting arm is received by the receiving arm, then the sensor is turned on and decides that the paper is loaded on the base. The pickup roller assembly will pick up the paper into the paper feeding device if a paper-picking signal is detected at the time.

However, the sensor and the obstructer of the conventional paper sensing unit are both arranged in the base, so a special connecting portion is needed to connect the obstructer. Therefore the components are increased, the structure of the paper feeding device is complex and is not convenient to be assembled.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a paper feeding device, comprising a supporting frame, a pickup roller assembly, a paper blocking unit, a base and a sensor. The supporting frame has a pair of supporting boards mounted on the inner surface of the supporting frame. A pair of retaining portions projects from the inner surface of the supporting frame. The retaining portions includes a pair of plate-shaped retaining boards paralleling to each other, a retaining hole is opened in the retaining board. The pickup roller assembly mounted between the supporting boards picks up paper and then transferring it into the paper feeding device. The paper blocking unit is placed beside the pickup roller assembly and has a paper blocking element. The paper blocking element includes a connecting portion with a pair of positioning pillars protruding from the two sides. The positioning pillar is rotatablely connected to the retaining hole of the retaining portion of the supporting frame. The connecting portion extends downwards to form a paper blocking arm. The base has a paper loading base. The sensor is located in the base for sensing whether a paper is loaded on the paper loading base, and has an emitting arm and a receiving arm. The lower portion of the paper blocking arm can be located between the emitting arm and the receiving arm or depart from the emitting arm and the receiving arm.

As described above, the sensor is in turn-off status when the lower portion of the paper blocking arm is located between the emitting arm and the receiving arm, the sensor is in turn-on status when the lower portion of the paper blocking arm departs from the emitting arm and the receiving arm, the paper feeding device decides whether the paper is provided on the base by the turn-on/turn-off status of the sensor, so an additional obstructer is avoided, compared with the conventional paper feeding device, the structure of the present invention is simple, and it is convenient to assemble.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which:

FIG. 1 is an exploded perspective view of a paper feeding device of the present invention;

FIG. 2 is a partial enlarged view of the encircled portion labeled 11 shown in FIG. 1;

FIG. 3 is a perspective view of a pickup roller assembly of the present invention;

FIG. 4 is a perspective view of a blocking element shown in FIG. 1;

FIG. 5 is a perspective view of a sensor of the present invention;

FIG. 6 is a cross-sectional view showing no paper loaded on a base of the paper feeding device; and

FIGS. 7-9 are cross-sectional views for describing operations of the paper feeding device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer to FIG. 1, the paper feeding device 1 of the present invention includes a supporting frame 10, a pickup roller assembly, a base 50 and a paper blocking unit 60.

Then please refer to FIG. 1 in combination with FIG. 2, the supporting frame 10 is placed above the base 50 and a paper transporting passage 52 (shown in FIG. 6) is formed therebetween. A pair of supporting boards 15 are mounted on the inner surface of the supporting frame 10 and a receiving space 14 is formed therebetween. A retaining portion 11 projects from the inner surface of the supporting frame 10. The retaining portion 11 include a pair of plate-shaped retaining boards 112 parallel to each other, and a restricting projection 113 is set therebetween. A retaining hole 111 is opened in the retaining board 112. Below the retaining portion 11, a pair of connecting portions 13 are mounted on the inner surface of the supporting boards 15.

Referring to FIG. 1 and FIG. 3, the pickup roller assembly includes a roller frame 40, a picking roller 20, a conveying roller 30 and a belt 21. The roller frame 40 has a first side wall 41 and a second side wall 42, an active shaft 43 and an idle shaft 44. One end of the active shaft 43 is fixed to the first side wall 41, the other end of the active shaft 43 is fixed to and pass through the second side wall 42 for receiving a driving force. One end of the idle shaft 44 is fixed to the first side wall 41, the other end of the idle shaft 44 is fixed to the second side wall 42. The idle shaft 44 is above the active shaft 43. A circle shaped restricting portion 425 projects from the inner surface of the second sidewall 42, a sleeve portion (not shown) projects from the inner surface of the second sidewall 42 and is above the restricting portion 425.

The conveying roller 30 is mounted around the active shaft 43 and one end of the conveying roller 30 is circled by the restricting portion 425. The picking roller 20 is mounted around the idle shaft 44 and one end of the picking roller 20 is connected to the sleeve portion. The belt 21 is sleeved on both the conveying roller 30 and the picking roller 20, and impels the conveying roller 30 and the picking roller 20 to press against the roller frame 40 for creating a friction between the conveying roller 30 and the restricting portion 425 and a friction between the picking roller 20 and the sleeve portion, which drives the roller frame 40 to rotate around the active shaft 43.

Please refer to FIG. 1 and FIG. 4, the paper blocking unit 60 includes a paper blocking element 61 and a projection 62. The paper blocking element 61 has a connecting portion 611. Two opposite sides of the connecting portion 611 project to form a positioning pillar 612 respectively. The front end of the connecting portion 611 extends upward to form a restricting arm 613. The restricting arm 613 leans against the restricting projection 113 of the supporting frame 10. The back end of the connecting portion 611 extends downwards to form a paper blocking arm 614 at the left, so an opening 615 is formed at the right of the paper blocking arm 614. The lower portion of the paper blocking arm 614 is cut off at the left and thus forms a board-shaped obstructer 616 at the right. The projection 62 is cylindrical and projects from the outer surface of the first side wall 41 of the pickup roller assembly 20.

Please refer to FIG. 1 and FIG. 6, a paper loading base 51 is formed at the front of the base 50 for loading papers, the paper loading base 51 extends backwards and defines the paper transporting passage 52 between the base 50 and the supporting frame 10. A long cavity 53 is lengthwise defined in the base 50 for receiving the obstructer 616.

Please refer to FIG. 1 and FIG. 5, the sensor 70 is electrically mounted on an electrical circuit board, the electrical circuit board is arranged in front of the cavity 53(as shown in FIG. 6). The sensor 70 is approximately U-shaped, including an emitting arm 71 and a receiving arm 72 parallel to the emitting arm 71. A connecting arm 73 connects the emitting arm 71 and the receiving arm 72 and is mounted on the electrical circuit board. The emitting arm 71 radiates light towards the receiving arm 72. The receiving arm 72 receives the light and turns on the sensor 70. 1n this embodiment, the sensor 70 is a light sensor, however, a contact sensor or an electromagnetic sensor can also be used as the sensor 70.

The assemblage of the paper feeding device 1 of the present invention is described hereinafter firstly, the pickup roller assembly is assembled together. Secondly, the pickup roller assembly is received in the receiving space 14 of the supporting frame 10, the left end of the active shaft 43 fixed to the first side wall 41 is rotatablely connected to one of the connecting portions 13 of the supporting frame 10, the right end of the active shaft 43 fixed to the second side wall 42 passes through the other connecting portion 13 of the supporting frame 10 for connecting with a driving component (not shown).

Then please refer to FIG. 6, the paper blocking unit 60 is placed beside the first side wall 41 of the pickup roller assembly, the positioning pillar 612 of the paper blocking element 61 is rotatablely connected to the retaining hole 111 of the supporting frame 10, the projection 62 stops at the connecting portion 611 of paper blocking element 61. Lastly, the supporting frame 10 covers on the base 50, the obstructer 616 of the paper blocking arm 614 stretches into the cavity 53 of the base 50, then the paper feeding device 1 of the present invention is assembled.

As shown in FIG. 6, when the paper feeding device 1 is in natural state, the picking roller 20 keeps a certain distance from the papers 2, the papers 2 are stopped outside by the paper blocking arm 614, the obstructer 616 is located between the emitting arm 71 and the receiving arm 72, so the light radiated from the emitting arm 71 is blocked by the obstructer 616, the sensor 70 keeps in a turn-off status.

Please refer to FIGS. 7-9, when the paper feeding device 1 picks up the paper 2, the driving force drives the active shaft 43 to rotate clockwise, so the pickup roller assembly rotates clockwise around the active shaft 43. When the paper is provided on the paper loading base 51, then the picking roller 20 contacts with the paper 2. Meanwhile, as the pickup roller assembly moves downwards, the projection 62 mounted on the first side wall 41 of the roller frame 40 also moves downwards and passes through the opening 615 of the paper blocking element 61, so the projection 62 loses cooperation with the paper blocking element 61, the paper blocking arm 614 rotates clockwise around the positioning pillar 612 and no longer stops the documents 2. When the belt 21 contacts with the document 2 and rotates clockwise, the friction created therebetween picks the document 2 into the paper transporting passage 52, then the front end of the paper 2 pushes the paper blocking arm 614 to rotate clockwise and depart from the sensor 70, as a result, the light radiated from the emitting arm 71 is received by the receiving arm 72, the sensor 70 is turned on, and the paper feeding device 1 continues to pick up the paper, during the rotation of the paper blocking arm 614, the projection 62 passes through the opening 615 (shown in FIG. 4) of the paper blocking element 61.

Please refer to FIG. 10, when the paper feeding device 1 picks up the paper 2 but no paper is provided on the paper loading base 51 or the paper is used up, the paper blocking arm 614 is in natural state under its own weight, and the obstructer 616 is located between the emitting arm 71 and the receiving arm 72, so the light radiated from the emitting arm 71 is blocked by the obstructer 616, the sensor 70 keeps in a turn-off status, as a result, the paper feeding device 1 stops to pick up papers. The driving force drives the active shaft 43 to rotate anti-clockwise, so the paper pickup assembly rotates anti-clockwise and moves upwards, so the picking roller 20 departs from the papers 2, meanwhile, the projection 62 projected from the roller frame 40 passes through the opening 615 again in a anti-direction (shown in FIG. 4) and stops at the connecting portion 611 of the paper blocking element 61, the restricting arm 613 stops at the restricting projection 113 of supporting frame 10, as shown in FIG. 6, the paper feeding device 1 returns to natural state.

As described above, the sensor 70 is in turn-off status when the obstructer 616 of the paper blocking arm 614 is located between the emitting arm 71 and the receiving arm 72, the sensor 70 is in turn-on status when the obstructer 616 of the paper blocking arm 614 departs from the emitting arm 71 and the receiving arm 72, the paper feeding device 1 decides whether the paper is provided on the base 50 by the turn-on/turn-off status of the sensor, so an additional obstructer is avoided. Compared with conventional paper feeding device, the structure of the present invention is simple and convenient to assemble.

The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to those skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims. 

1. A paper feeding device, comprising: a supporting frame, having a pair of opposite supporting boards mounted on the inner surface of the supporting frame; a retaining portion projecting from the inner surface of the supporting frame, the retaining portion including a pair of retaining boards parallel to each other, a retaining hole being opened in the retaining board; a pickup roller assembly mounted between the supporting boards, picking up and then transferring papers into the paper feeding device; a paper blocking unit placed beside the pickup roller assembly, having a paper blocking element, the paper blocking element including a connecting portion with a pair of positioning pillars protruding from the two sides, the positioning pillar rotatablely connected to the retaining hole of the retaining portion of the supporting frame, the connecting portion extending downwards to form a paper blocking arm; a base having a paper loading base; and a sensor located in the base for sensing whether a paper is loaded on the paper loading base, having an emitting arm and a receiving arm; wherein the lower portion of the paper blocking arm can be located between the emitting arm and the receiving arm or depart from the emitting arm and the receiving arm.
 2. The paper feeding device as claimed in claim 1, wherein the front end of the connecting portion of the paper blocking element extends upward to form a restricting arm, a restricting projection is set between the retaining boards, the restricting arm leaning against the restricting projection.
 3. The paper feeding device as claimed in claim 1, wherein the back end of the connecting portion of the paper blocking element extends downward to form the paper blocking arm at the left, so an opening is formed at the right of the paper blocking arm, the pickup roller assembly includes a roller frame, the paper blocking unit further comprises a projection protruding from the sidewall of the roller frame, the projection can stop at the connection portion of the paper blocking arm or pass through the opening of the paper blocking arm.
 4. The paper feeding device as claimed in claim 3, wherein the lower portion of the paper blocking arm is cut off at the left and thus forms a board-shaped obstructer at the right, the obstructer located between or depart from the emitting arm and the receiving arm.
 5. The paper feeding device as claimed in claim 1, wherein the receiving arm is parallel to the emitting arm and is connected by a connecting arm mounted on an electrical circuit board. 